Publications by authors named "Rachel Sacks Davis"

Background: Historically, hepatitis C virus (HCV) was difficult to treat among people with HIV. However, treatment with direct-acting antivirals (DAAs) results in 90%-95% of people being cured. There is a need to understand why a proportion of people are not cured.

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People with a history of injecting drug use are a priority for eliminating blood-borne viruses and sexually transmissible infections. Identifying them for disease surveillance in electronic medical records (EMRs) is challenged by sparsity of predictors. This study introduced a novel approach to phenotype people who have injected drugs using structured EMR data and interactive human-in-the-loop methods.

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Article Synopsis
  • People who inject drugs generally experience worse health outcomes, and this study aimed to analyze the factors leading to participant attrition in a cohort study in Victoria, Australia.
  • The research utilized data from the Melbourne Injecting Drug User Cohort Study (SuperMIX) and found that 36.8% of participants were lost to follow-up within two years, particularly among younger individuals and those facing social and economic challenges.
  • The results indicate that while attrition rates have been stable, vulnerable groups may be underrepresented in the data, highlighting the need for strategies to keep these high-risk individuals engaged in the study.
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Background & Aims: Hepatocellular carcinoma (HCC) presents a significant global health challenge, particularly among individuals with liver cirrhosis, with hepatitis C (HCV) a major cause. In people with HCV-related cirrhosis, an increased risk of HCC remains after cure. HCC surveillance with six monthly ultrasounds has been shown to improve survival.

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Introduction: Despite universal access to government-funded direct-acting antivirals (DAAs) in 2016, the rate of hepatitis C treatment uptake in Australia has declined substantially. Most hepatitis C is related to injecting drug use; reducing the hepatitis C burden among people who inject drugs (PWID) is, therefore, paramount to reach hepatitis C elimination targets. Increasing DAA uptake by PWID is important for interrupting transmission and reducing incidence, as well as reducing morbidity and mortality and improving quality of life of PWID and meeting Australia's hepatitis C elimination targets.

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Objective: Guidelines recommend annual hepatitis C virus (HCV) testing for gay and bisexual men (GBM) with HIV and GBM prescribed HIV pre-exposure prophylaxis (PrEP). However, there is a limited understanding of HCV testing among GBM. We aimed to examine trends in HCV testing and positivity from 2016 to 2022.

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Introduction: A disproportionate number of COVID-19 deaths occur in Residential Aged Care Facilities (RACFs), where better evidence is needed to target COVID-19 interventions to prevent mortality. This study used an agent-based model to assess the role of community prevalence, vaccination strategies, and non-pharmaceutical interventions (NPIs) on COVID-19 outcomes in RACFs in Victoria, Australia.

Methods: The model simulated outbreaks in RACFs over time, and was calibrated to distributions for outbreak size, outbreak duration, and case fatality rate in Victorian RACFs over 2022.

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The impact of outbreak response immunization (ORI) can be estimated by comparing observed outcomes to modelled counterfactual scenarios without ORI, but the most appropriate metrics depend on stakeholder needs and data availability. This study developed a framework for using mathematical models to assess the impact of ORI for vaccine-preventable diseases. Framework development involved (1) the assessment of impact metrics based on stakeholder interviews and literature reviews determining data availability and capacity to capture as model outcomes; (2) mapping investment in ORI elements to model parameters to define scenarios; (3) developing a system for engaging stakeholders and formulating model questions, performing analyses, and interpreting results; and (4) example applications for different settings and pathogens.

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Background: In Australia, the incidence of hepatitis C virus (HCV) has declined among gay and bisexual men (GBM) with human immunodeficiency virus (HIV) since 2015 and is low among GBM using HIV preexposure prophylaxis (PrEP). However, ongoing HCV testing and treatment remains necessary to sustain this. To assess the potential utility of sexually transmissible infections (STIs) to inform HCV testing among GBM with HIV and GBM using PrEP, we examined the association between bacterial STI diagnoses and subsequent primary HCV infection.

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Background: Hepatitis C virus (HCV) infections are more prevalent in people who inject drugs (PWID) who often experience additional health risks. HCV induces inflammation and immune alterations that contribute to hepatic and non-hepatic morbidities. It remains unclear whether curative direct acting antiviral (DAA) therapy completely reverses immune alterations in PWID.

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Article Synopsis
  • - The study examined hepatitis C virus (HCV) reinfection rates among gay and bisexual men (GBM) with HIV in Australia from 2016 to 2020, amidst concerns about the impact of reinfection on HCV micro-elimination efforts.
  • - Data were collected from 39 clinics, revealing that out of 12,213 GBM with HIV, 540 were eligible for reinfection analysis, with 38 (7%) showing evidence of reinfection during the study period, resulting in a reinfection rate of 3.4 cases per 100 person-years.
  • - The results indicated a 30% average annual decline in HCV reinfection incidence since the introduction of government-funded direct-acting antiviral
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Article Synopsis
  • The study investigates HCV reinfection rates among HIV-positive individuals after the introduction of direct-acting antivirals (DAAs) and determines how much of the new HCV cases are due to reinfections.
  • Using data from six international cohorts, researchers analyzed the incidence of HCV reinfection before and after DAAs became widely available, focusing on patient demographics and reinfection timelines.
  • Results showed that the incidence of HCV reinfection remained stable before the introduction of DAAs, with a follow-up of 6144 HIV-positive participants over more than 17,000 person-years.
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Background: Among people living with HIV and hepatitis C virus (HCV), people who inject drugs (PWID) have historically experienced higher mortality rates. Direct-acting antivirals (DAA), which have led to a 90 % HCV cure rate independently of HIV co-infection, have improved mortality rates. However, DAA era mortality trends among PWID with HIV/HCV remain unknown.

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Article Synopsis
  • Gay and bisexual men taking HIV PrEP are at a higher risk for sexually transmitted infections, but the risk of Hepatitis C (HCV) among these users has not been well defined.
  • A systematic review and meta-analysis of studies found the HCV prevalence among PrEP users is relatively low, with the baseline prevalence of HCV antibodies at 0.97% and HCV RNA at 0.38%.
  • Incidence rates of HCV were generally higher in studies conducted before the widespread availability of direct-acting antiviral therapy, indicating that local healthcare resources and timing can significantly impact infection rates.
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Background: Peers are an important determinant of health and well-being during late adolescence; however, there is limited quantitative research examining peer influence. Previous peer network research with adolescents faced methodological limitations and difficulties recruiting young people.

Objective: This study aims to determine whether a web-based peer network survey is effective at recruiting adolescent peer networks by comparing 2 strategies for reimbursement.

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Background: Microelimination of the hepatitis C virus (HCV) among men who have sex with men (MSM) could be complicated by continuous external introductions and the emergence of phylogenetic clusters harbouring clinically significant resistance-associated substitutions (RAS). To investigate international clustering and the prevalence and transmission of RAS, we aimed to analyse whole-genome HCV sequences from MSM with a recently acquired infection who participated in a large, international HCV treatment trial.

Methods: For this whole-genome analysis, we obtained HCV sequences from 128 MSM who had acquired HCV within the past 12 months and were participating in the REACT trial.

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Background: In 2021, the Australian Government Department of Health commissioned a consortium of modelling groups to generate evidence assisting the transition from a goal of no community COVID-19 transmission to 'living with COVID-19', with adverse health and social consequences limited by vaccination and other measures. Due to the extended school closures over 2020-21, maximizing face-to-face teaching was a major objective during this transition. The consortium was tasked with informing school surveillance and contact management strategies to minimize infections and support this goal.

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Background: Policy responses to COVID-19 in Victoria, Australia over 2020-2021 have been supported by evidence generated through mathematical modelling. This study describes the design, key findings, and process for policy translation of a series of modelling studies conducted for the Victorian Department of Health COVID-19 response team during this period.

Methods: An agent-based model, Covasim, was used to simulate the impact of policy interventions on COVID-19 outbreaks and epidemic waves.

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Background: Measuring the incidence of HIV and hepatitis C virus (HCV) infection among people who inject drugs (PWID) is key to track progress towards elimination. We aimed to summarise global data on HIV and primary HCV incidence among PWID and associations with age and sex or gender.

Methods: In this systematic review and meta-analysis, we updated an existing database of HIV and HCV incidence studies among PWID by searching MEDLINE, Embase, and PsycINFO, capturing studies published between Jan 1, 2000, and Dec 12, 2022, with no language or study design restrictions.

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Background: Individuals with HIV and hepatitis C virus (HCV) who remain untreated with direct-acting antivirals can contribute to HCV transmission and HCV-related mortality. We aimed to compare rates of uptake of direct-acting antivirals following unrestricted access to this treatment in high-income countries and examine factors associated with remaining untreated.

Methods: This multinational, prospective cohort study used data from the International Collaboration on Hepatitis C Elimination in HIV Cohorts (InCHEHC).

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Objective: To estimate the proportion of Victorians infected with COVID-19 in January 2022.

Methods: Between 11-19 February 2022 we conducted a nested cross-sectional survey on experiences of COVID-19 testing, symptoms, test outcome and barriers to testing during January 2022 in Victoria, Australia. Respondents were participants of the Optimise Study, a prospective cohort of adults considered at increased risk of COVID-19 or the unintended consequences of COVID-19-related interventions.

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Background: Broad direct-acting antiviral (DAA) access may reduce hepatitis C virus (HCV) incidence through a "treatment as prevention" (TasP) effect. We assessed changes in primary HCV incidence following DAA access among people living with HIV (PLHIV).

Methods: We used pooled individual-level data from six cohorts from the International Collaboration on Hepatitis C Elimination in HIV Cohorts (InCHEHC).

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Article Synopsis
  • In 2020, Victoria experienced extensive COVID-19 lockdowns, significantly impacting the testing for hepatitis C among people who inject drugs (PWID).
  • Data from 11 specialized services showed a notable decrease in weekly antibody and RNA testing after both lockdowns, with drops of 31% and 46% after the first lockdown and 26% and 33% after the second.
  • The missed testing opportunities during these lockdowns pose a challenge for Australia in meeting hepatitis C elimination targets, potentially delaying the identification and treatment of affected individuals in the PWID community.
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  • This study investigates trends in hepatitis C virus (HCV) incidence among primary care patients over time to assess public health strategies for HCV elimination.
  • Researchers analyzed data from 6711 patients, identifying 210 new HCV infections and calculating an overall incidence rate of 1.1 per 100 person-years, with higher rates in patients prescribed opioid-related pharmacotherapy.
  • The findings indicate a decline in HCV incidence from 2009 to 2020, suggesting improvements in public health efforts, particularly with increased access to direct-acting antiviral (DAA) therapy.
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